Tap-changing system



April 16, 1929.- 1,709,667

r I YTAP CHANGING SYSTEM Filed July .14, 9 8 Z'Sheets-Sheet 1 INVENTOR 1mm I'll W AT'OREY April 16, 1929.

L. H. HILL TAP CHANGING SYSTEM Filed July 14, 1928 2 Sheets-Sheet 2INVENTOR Leland H H/'// ATTORNEY Patented pr. 16, 192a LELAND H. HILL,OF COLLINGSWOOD, NEW JERSEY, ASSIGNOR TO WESTINGHOUSE ELECTRIC &MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

T-CHANGING SYSTEM.

Application filed July 14 My invention relates to tap changing mechanismfor electric transformers and more particularly to means for manuallyoperating remotely controlled tap changing mechanism.

An object of my invention is to provide means for protecting an operatorfrom 1njury by the operation of a normally remotely controlled tapchanging mechanism.

Another object of my invention is to simplify tap changing equipmentwhen the latter is designed forboth automatic and 'manual operation.

A further object of my invention is to provide means for remotelydisconnecting the energizing circuit to a control motor, me-

chanically releasing and maintaining released a brake for said motor,and operating a signal, when normally remotely controlled tap changingmechanism is placed in condition for manual operation by the lowering ofa cover normally'protecting a handwheel on the shaft of said motor.

These and other useful and desirable object-s will be set forth in thefollowing description of my invention when taken in connection with theaccompanying drawings.

In the drawings:

Figure 1 is a diagrammatic view of tap changing equipment constructed inaccordance with my invention, and

Fig. 2 is a semi-diagrammatic perspective view of the equipmentillustrated in Fig. 1.

Referring to Fig. 1 there is illustrated a transformer T comprising ahigh tension or primary winding P and a low tension or secondary windingS. Goactively related with the transformer T and particularly its lowtension winding S is a compensating windingor auto-transformer C.

Winding S comprises a main section and a plurality of sub-sectionsformed by properly connecting conductors 1, 2, 3, 4, 5 and 6 thereto.Interposed in the respective conductors 2, 8, 4:, 5 and 6 are theswitches or circuit breakers 7, 8, 9, 10 and 11. Conductors 2, 4 and 6lead to a common conductor 12 connected to one terminal of the winding Cwhile conductors 3 and 5 lead to a common conductor 13 connected to theother terminal of winding 0. Connected preferably to the mid-point ofwinding G is a conductor 14 which, with conductor 1,

circuit. In actual practice, the conductor 14 forms the line conductorsof the secondary.

, 1928. Serial No. 292,769.

connected to the grounded end of a star-connected winding or themiddleof a winding connected in delta relation with similar transformerwindings.

suitably supported in bearings, not shown, has keyed or otherwisesuitably secured thereto a plurality of spaced members or cams 16, 17,18, 19 and 20 adapted, upon a turning of shaft 15 to actuate the linkand toggle mechanisms 21, 22, 23, 24 and 25, respectively, and therebyto positively close and open the respective switches 7, 9, 8, 11 and 10in a predetermined sequence. Preferably, the shaft 15 makes less thanone complete revolution for the whole range of tap changing.

In the example illustrated, shaft'15 may be moved into nine difl'erentpositions 'to thereby operate the various switches and bring thewindings S and G into a like number of difl'erent coacting relations.For purposes of ready reference, the difierent positionsof shaft 15 andthe resulting conditlon of the switches are here tabulated as follows:

Position No. Closes switch BN0.

1 11 2 11 and 10 3 10 4 10 and 9 6 9 and 8 7 8 8 8 and 7 9 7 With theshaft 15 in position No. 1, the

voltage across the secondary circuit is at its maximum value. When saidshaft is in position No. 2, the winding 0 coacts with winding S in suchmanner that the voltage across the secondary circuit is the aforesaidmaxi-. mum value less the voltage which would be induced in one half ofthe sub-section of winding S between the conductors 6 and 5. With theshaft 15 in position No. 3, the entire sub-section of winding S betweenconductors 6 and 5, is eliminated and, therefore, the effective part ofwinding S is that between the conductors 1 and 5. Thus, as shaft 15 ismoved successively to position Nos. 4,

- 5, 6, 7, 8 and '9, the voltage across the sec- Referring to Figs. 1and 2, a shaft,15

. wit-ha gear 27 secured to one end of a shaft 28 to the other end ofwhich a gear 29 is secured.

Meshing with the gear 29 is -a worm 30 rotatable with a shaft 31 mountedin suitable bearings, not shown. The rotatable element of a motor 32 issecured preferably to one end of the aforesaid shaft 31 While to theother end thereof a hand wheel 33 is secured.

Secured to the shaft 31 is a drum 34 with which coacts a brake orfriction band 35, one end of which is secured to a fixed support 36.Extending from the other, or movable end of the band 35 is a rod 37slidable in a bracket 38 and connected. to the armature of anelectromagnct 39. A helical spring 40, disposed between the bracket 38and the aforesaid movable end of band 35, biases the latter to a brakingposition on the drum 34.

Pivoted at 41 to a suitable support, not shown, is a member or cover 42which, when in the position illustrated in Fig. 2 prevents access to,and manual operation of the hand wheel 33. By preference, cover 42 ispositively retained in the position illustrated in Fig. 2 by a lock 43.

A rod 44 rotatable in bearings 45 has secured to one end thereof anactuating member or cam 46 adapted for coaction with the movable end ofband 35. The other end 44a of rod 44 is disposed upon a member 47,comprising an inclined portion 47a, and an extension 47 b, of the member47 is slidably mounted in a supporting member 48, between which and theportion 470, a helical spring 49 is confined for biasing the member 47into engagement with an extension or lug 50 carried by or movable withthe cover 42.

When lock 43 is released, the cover 42 may be swung downwardly (Fig. 2)with resultant movement of lug 50 of the member 47. As a result, themember 47, under the influence of the spring 49, moves toward the right,Fig. 2, and the inclined position 47a of member 47 rotates rod 44 insuch a direction that the cam 46 releases the brake band from the drum34. The hand wheel 33 may now be operated to rotate the shaft 31, andthereby, to move the shaft 15 into any one of its several positions,whereby the desired voltage may be maintained across the secondarycircuit. When the cover 42 is returned to the position illustrated inFig. 2, the inclined face 470: of member 47 is remower moved from theend 44a of rod 44, and the band 35 is tightened upon the drum 34, by thespring 40. Thus, the various parts are positively retained or locked inthe selected position. I

A lowering of the cover 42 also breaks a circuit through the conductors01 and 50a to the motor 32, by permitting a spring 51 to move aswitching member 52 away from contacts 53 and 54 in the circuit 50a. Themotor 32 is thereby deenergized and may be freely turned by thehandwheel The switching member 52 when moved by the spring 51, as thecover 42 is lowered, closes a circuit between contacts 55 and 56, andconnects them in series circuit relation with a lamp L throughconductors 57, 5S and 59. The conductors 57 and 58 are connected toconductors 60 and 61, respectively, of the supply conductors 60, 61 and62. .Vhen the cover 42 is lowered, the lamp L, mounted on a panelboard,lights, indicating that the tap changer is in the proper position forhand operation and remote control is impossible.

The spring 51 may, of course, be associated with the switching member 52and the cover 42 in any suitable manner, but by preference a bent rod 64has the switching member 52 secured thereto at one end and coacts withan extension 65 on the cover 42 to open and 'close circuits through thecontacts 55 and 56, and 53 and 54, respectively, against the force ofthe spring 51 when the cover 42 is moved to its closed position.

- When the cover 42 is closed the handwheel 33 is free to turn with theoperation of the shaft 31 by the motor 32, which is preferablyautomatically controlled from a source of electrical energy (not shown)through a circuit represented by conductors 60, 61 and 62. Operatorsworking near the handwheel 33 are thereby protected from injury due to aturning of the same.

However, when it is desired to move the tap changing mechanism by hand asimple lowering of the cover 42 disconnects the motor 32, releases thebrake drum 34, lights the lamp L and permits the handwheel 33 to beturned by the operator". After turning the handwheel 33 any desiredamount, the apparatus is restored to normal condition for automaticoperation by simply closing the cover 42.

As heretofore mentioned the cover 42 may be provided with a lock 43 toprevent an unauthorized lowering of the cover 42.

It will be apparent to those skilled in the art that various minorchanges may be made in my invention without departing from the spiritthereof. 1 wish my invention, therefore, to be limited only by the scopeof the appended claims.

1 claim as my invention 1. In combination, a winding provided with tapsand switching means for changing moaew the circuit connections to saidtaps, means comprising awinding provided with taps,

tap changing means for changing circuit connections to said taps, meansincluding a motor and a hand lever for operatin said tap changing means,means for braking said operating means, a cover for said hand lever, andmeans for electrically disconnecting said motor and mechanicallydisconnecting said braking means upon movement of said cover to such aposition as to render said hand lever accessible for operation.

3. In combination, a cam-operated tap changing device, means including amotor and a handwheel on the same shaft for operating said device, anelectromagnetically controlled brake for said shaft, a cover for saidhandwheel, and means including a mechanical interconnection between saidbrake and said cover for rendering said brake inoperative when saidcover is opened.

4. In combination, means for tap changing, means including a motorhaving a control circuit for automatically operating said tap changer,and means for manually operating said tap changer comprising a levermechanically connected to the armature of said motor, a cover for saidlever, and means associated with said cover for opening and closing onepoint of said motor control circuit, when said cover is opened andclosed, respectively.

5. In combination, means for tap chang' ing, means including a motorhaving a control circuit and a hand lever for turning said tap changingmeans, a brake for said motor,

means for housing said hand lever, means associated with said housing,means for opening and closmg said motor control circuit when saidhousing means 1s opened and closed, respectively, and means formaintaining said brake released when said housing means is open.

6. In combination with a tap changing Inechanism'for a transformer, amotor for .driving said mechanism, a brake for said motor, a signal, ahandwheel for turning said motor, and a cover for said handwheel, ofmeans for deenergizing said motor, rcleasing said brake, and operatingsaid signal when said cover is opened, and means for restoring saidmechanism for normal operation when said cover is closed. I

In testimony whereof, I have hereunto subscribed my name this 10th dayof July,

. LELAND H. HILL.

